In the classical music sense, yes. Really, though, and having performed it more than once with multiple interpretations, it's really more theatrical than reverent and was part of a movement that was corrected in the 19th century when chant was once again emphasized over "performance" level pieces, which the Mozart Requiem clearly is. This is part of the reason that classical music doesn't have so many Masses in the eras since.
Agreed, this also tosses Gounod, et al, out of the picture.
My larger point is that there is a definite place for Gregorian and other forms of chant and there is a definite place for hymnody, regardless of the Christian source. My own hymnal has hymns from Ephraem Syrus, Bach, Mozart, Haydn, Ralph Vaughn Williams, Charles Wesley, Martin Luther and many many Roman ones. I am happy to see the Roman congregations being encouraged to move from the trivial show tunes now in use back toward reverent hymans. I am not so happy to see the Roman Church use this as one more way to exclude anything not explicitly produced by a Roman. It’s just not charitable and it really does rule out some of the most beautiful and reverent music ever composed.